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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
+ "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
+<refentry id="glHint">
+ <refmeta>
+ <refmetainfo>
+ <copyright>
+ <year>1991-2006</year>
+ <holder>Silicon Graphics, Inc.</holder>
+ </copyright>
+ </refmetainfo>
+ <refentrytitle>glHint</refentrytitle>
+ <manvolnum>3G</manvolnum>
+ </refmeta>
+ <refnamediv>
+ <refname>glHint</refname>
+ <refpurpose>specify implementation-specific hints</refpurpose>
+ </refnamediv>
+ <refsynopsisdiv><title>C Specification</title>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>void <function>glHint</function></funcdef>
+ <paramdef>GLenum <parameter>target</parameter></paramdef>
+ <paramdef>GLenum <parameter>mode</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+ <refsect1 id="parameters"><title>Parameters</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>target</parameter></term>
+ <listitem>
+ <para>
+ Specifies a symbolic constant indicating the behavior to be controlled.
+ <constant>GL_LINE_SMOOTH_HINT</constant>,
+ <constant>GL_POLYGON_SMOOTH_HINT</constant>,
+ <constant>GL_TEXTURE_COMPRESSION_HINT</constant>, and
+ <constant>GL_FRAGMENT_SHADER_DERIVATIVE_HINT</constant>
+ are accepted.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>mode</parameter></term>
+ <listitem>
+ <para>
+ Specifies a symbolic constant indicating the desired behavior.
+ <constant>GL_FASTEST</constant>,
+ <constant>GL_NICEST</constant>, and
+ <constant>GL_DONT_CARE</constant> are accepted.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1 id="description"><title>Description</title>
+ <para>
+ Certain aspects of GL behavior,
+ when there is room for interpretation,
+ can be controlled with hints.
+ A hint is specified with two arguments.
+ <parameter>target</parameter> is a symbolic
+ constant indicating the behavior to be controlled,
+ and <parameter>mode</parameter> is another symbolic constant indicating the desired
+ behavior. The initial value for each <parameter>target</parameter> is <constant>GL_DONT_CARE</constant>.
+ <parameter>mode</parameter> can be one of the following:
+ </para>
+ <variablelist>
+ <varlistentry>
+ <term><constant>GL_FASTEST</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ The most efficient option should be chosen.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_NICEST</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ The most correct,
+ or highest quality,
+ option should be chosen.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_DONT_CARE</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ No preference.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <para>
+ Though the implementation aspects that can be hinted are well defined,
+ the interpretation of the hints depends on the implementation.
+ The hint aspects that can be specified with <parameter>target</parameter>,
+ along with suggested semantics,
+ are as follows:
+ </para>
+ <variablelist>
+ <varlistentry>
+ <term><constant>GL_FRAGMENT_SHADER_DERIVATIVE_HINT</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ Indicates the accuracy of the derivative calculation for the GL shading language fragment processing built-in functions:
+ <constant>dFdx</constant>, <constant>dFdy</constant>, and <constant>fwidth</constant>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_LINE_SMOOTH_HINT</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ Indicates the sampling quality of antialiased lines.
+ If a larger filter function is applied, hinting <constant>GL_NICEST</constant> can
+ result in more pixel fragments being generated during rasterization.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_POLYGON_SMOOTH_HINT</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ Indicates the sampling quality of antialiased polygons.
+ Hinting <constant>GL_NICEST</constant> can result in more pixel fragments being generated
+ during rasterization,
+ if a larger filter function is applied.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_COMPRESSION_HINT</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ Indicates the quality and performance of the compressing texture images.
+ Hinting <constant>GL_FASTEST</constant> indicates that texture images should be compressed
+ as quickly as possible, while <constant>GL_NICEST</constant> indicates that texture images
+ should be compressed with as little image quality loss as possible.
+ <constant>GL_NICEST</constant> should be selected if the texture is to be retrieved by
+ <citerefentry><refentrytitle>glGetCompressedTexImage</refentrytitle></citerefentry> for reuse.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1 id="notes"><title>Notes</title>
+ <para>
+ The interpretation of hints depends on the implementation.
+ Some implementations ignore <function>glHint</function> settings.
+ </para>
+ </refsect1>
+ <refsect1 id="errors"><title>Errors</title>
+ <para>
+ <constant>GL_INVALID_ENUM</constant> is generated if either <parameter>target</parameter> or <parameter>mode</parameter> is not
+ an accepted value.
+ </para>
+ </refsect1>
+ <refsect1 id="Copyright"><title>Copyright</title>
+ <para>
+ Copyright <trademark class="copyright"></trademark> 1991-2006
+ Silicon Graphics, Inc. This document is licensed under the SGI
+ Free Software B License. For details, see
+ <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
+ </para>
+ </refsect1>
+</refentry>
HCoop / clinton / guile-figl.git / blobdiff